code: def nerf_model():
      return NerfModel(
          num_ray_points=11,
          num_pos_freqs=10,
          num_dir_freqs=4,
          num_units=2,
          num_unit_layers=4,
          num_hidden=256,
      )
  
file_path: kornia/test/nerf/test_nerf_model.py
imports: import pytest
  import torch
  from kornia.geometry.camera import PinholeCamera
  from kornia.nerf.nerf_model import MLP, NerfModel, NerfModelRenderer
label_desc: Use image node_id 1 for calling a global function with example usage: nerf_model() and returns: NerfModel